CN203021345U - Device for fine treatment of water produced by thin interbed low-permeability oilfield adopting ceramic membrane - Google Patents

Abstract

The utility model discloses a device for fine treatment of water produced by a thin interbed low-permeability oilfield adopting a ceramic membrane. Sewage containing oil produced by the thin interbed low-permeability oilfield is conveyed to an oil sewage tank; the sewage containing oil is lifted to enter into a ceramic membrane assembly filter through a circulating pump; the sewage containing oil produced by the thin interbed low-permeability oilfield is processed by the ceramic membrane assembly filter in parallel or in series; the ceramic membrane assembly filter adopts a cross flow filtering mode; the sewage containing oil flows at high speed on the surface of an inner side membrane of a membrane tube under the drive of pressure; the sewage containing oil is purified through the ceramic membrane layer along the direction vertical to the ceramic membrane layer; the purified water is input into a sewage injection system; macromolecular substances or solid particles are intercepted by the membrane, return to the oil sewage tank under rinsing of the sewage containing oil flowing at the high speed, and enter the ceramic membrane assembly filter again to begin the next filter process after being mixed with the newly added sewage containing oil; the purified water yield is further increased; and the sewage injection system continues to convey the injected water containing A1 level of water.

Description

A device for finely treating produced water in thin interbedded low-permeability oilfields with ceramic membranes

technical field

The utility model relates to a device for finely treating produced water in thin interbedded low-permeability oilfields with ceramic membranes, specifically applying ceramic membrane separation technology to the fine treatment of produced water in thin interbedded low-permeable oilfields to ensure thin interbedded low-permeable oilfields The produced water produced in the oilfield development process can stably reach the A1 level reinjection index after treatment.

Background technique

At present, the domestic low-permeability oilfield produced water reinjection treatment technology must ensure that the water quality after treatment reaches the A1 water quality standard, that is, the oil content is ≤5.0mg/L, the suspended solid content is ≤1.0 mg/L, and the median particle size of suspended solids is ≤ 1.0μm, average corrosion rate < 0.076mm/a, but in fact it cannot reach the water quality standard of A1 level, and a few water treatment technologies can only reach the water quality standard of A2 level. Due to the lack of on-site treatment devices for small cut-off and low-permeability blocks, the produced water from low-permeability blocks is often piped to the sewage station for treatment and then sent back to the low-permeability block for reinjection. This method not only increases energy consumption, but also easily Cause secondary pollution of water quality along the way, making it difficult for wellhead water quality to meet the standard. The utility model is developed in view of the above problems, and aims to further improve the treatment effect of produced water in thin interbedded low permeability oilfields, and improve the water injection development recovery rate of thin interbedded low permeability oilfields.

Contents of the invention

The purpose of the utility model is to provide a ceramic membrane device for finely treating the produced water of thin interbedded low-permeability oilfields, so as to overcome the shortcomings of the prior art in the above-mentioned oilfields. In order to meet the treatment requirements of different water quality, the core treatment unit of the device—the ceramic membrane is surface modified, the pore size of the ceramic membrane is optimized, and the series and parallel connection of ceramic membrane modules are reasonably adopted to improve the treatment efficiency, ensure the water quality of the effluent, and reduce the The processing cost is reduced, and the application range of the device is broadened.

The technical scheme of the utility model is realized in the following ways:

A device for finely treating produced water in thin interbedded low-permeability oilfields with ceramic membranes. It is a device for finely treating produced water in thin interbedded low-permeable oilfields with ceramic membranes. Composed of ceramic membrane modules, flowmeters, circulation pumps, sewage pumps, mixers, electric valves and skids, it is characterized in that the rear top surface of the skids is equipped with oily sewage tanks and ceramic membrane module filters with parallel and series processes. On the front top surface of the skid, there are cleaning water tanks, lye tanks and acid tanks arranged in a line; the oily sewage tank inlet is connected to the oily sewage water pipeline, and the outlet is respectively connected to the ceramic membrane module filter through the circulation pump and flow meter The inlet with pressure sensor is connected, the filtered purified water outlet of the ceramic membrane module filter is connected in parallel with the sewage reinjection system through the pressure sensor and the electric valve, and the sewage outlet filtered by the ceramic membrane module filter is connected in parallel with the oily sewage tank The backflow inlet is connected, the sewage outlet of the oily sewage tank is connected with the sewage pump, and the sewage pump outlet is connected with the dirty oil pool outside the skid block; the outlets of the cleaning water tank, the alkali tank and the acid tank are connected in parallel with the inlet of the circulation pump, and the above three tanks return The inlet is connected to the outlet pipe of the sewage filtered by the ceramic membrane module filter in parallel through the electric valve and flowmeter; the control circuit of the circulation pump and the sewage pump, the pressure sensor of the oily sewage inlet of the ceramic membrane module filter and the filtered water The outlet pressure sensor signal line and all electric valve control lines are connected to the PLC control cabinet.

The ceramic membrane module filter housing is set in a cylindrical shape, the oily sewage inlet is set at the top middle, the filtered water outlet is set at the middle and lower part of the cylinder, and the sewage outlet is set at the bottom middle; the oily sewage tank oily sewage inlet is set at On the top of the tank, the oily sewage outlet and sewage outlet are set at the bottom of the tank, and the return port is set at the top of the tank; the outlets of the cleaning water tank, lye tank and pickling tank are set at the bottom of the tank, and the return inlet is set at the top of the tank.

working principle:

Send the oily sewage produced from the thin interlayer low permeability oil field into the oily sewage tank, and then lift the oily sewage into the ceramic membrane module filter through the circulating pump, and use the ceramic membrane module in parallel or in series to filter according to the water quality and effluent requirements The device treats oily sewage produced from thin interlayer low permeability oil fields; the ceramic membrane module filter adopts the cross-flow filtration method, and the oily sewage flows at a high speed on the surface of the membrane layer inside the membrane tube under the pressure drive, and the oily sewage flows along the vertical direction of the ceramic membrane layer. The direction of purification is generated through the ceramic membrane layer, and the purified water is input into the sewage reinjection system. The macromolecular substances or solid particles are intercepted by the membrane, and returned to the oily sewage tank under the high-speed flow of oily sewage, and mixed with the newly added oily sewage. Then re-enter the ceramic membrane module filter to start the next filtration process, further increase the yield of purified water, and continuously deliver reinjection water that meets the A1 water quality to the sewage reinjection system.

The ceramic membrane module is made into a cylindrical shape after three times of film coating and three times of sintering modification. Vertical holes are uniformly arranged from top to bottom, and the outer periphery of each vertical hole is equipped with nano-scale micropores to strengthen the "hydrophilic and oil-repellent" of the ceramic membrane. "performance, improve water flux; the ceramic membrane adopts a high-speed multi-channel filtration system, which reduces the chance of oil droplets and suspended solids concentrating on the membrane surface, speeds up the separation of oil, water, and solid particles, and increases the yield of purified water.

The series-parallel ceramic membrane module filter is used to purify the water unit to increase the yield of purified water and reduce the discharge of sewage; when the flux of the ceramic membrane drops to a certain level, it is necessary to empty the sewage in the oily water tank and add new oily sewage Treatment is carried out to increase the membrane flux; and when the membrane flux is reduced to the point where the oily sewage cannot be treated, even if the sewage is discharged, the flux cannot be restored, and the chemical cleaning agent is used to restore the ceramic membrane module filter.

The utility model is not affected by the water quality of the incoming water, and can be applied to any process section of the sewage station, and can also be applied to the in-situ treatment of the produced water in remote, small fault block and low-permeability oil fields, and can ensure that the water quality of the treated water reaches A1-level indicator requirements. The utility model can greatly shorten the process flow of oilfield reinjection water treatment, and reduce the area occupied by the equipment. According to calculations, the scale of sewage treatment of 1000m ³ /d can save a one-time investment of 3 to 4 million yuan; in addition, the utility model is pure Physical filtration does not need to add any chemicals during the filtration process, does not produce oily sludge, and is different from the traditional method of separate treatment of oil and suspended solids, this technology can remove suspended solids and dirty oil at one time. According to calculations, 1000m ³ /d sewage treatment scale can save about 800,000/year operating costs.

After the implementation of this technology, it can ensure that the effluent after oily sewage treatment can reach the A1 water injection index stably, meet the development needs of thin interbedded low permeability oilfields, improve the recovery rate of thin interbedded low permeability oilfields, and promote the development of thin interbedded low permeability oilfields. long-term stable production growth.

Description of drawings

Figure 1 — Schematic diagram of ceramic membrane filtration process;

In the figure 1- oily sewage tank, 2, 3- ceramic membrane module filter, 4, 5- flow meter, 6- circulation pump 7, 8, 9, 10, 11- pressure sensor, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22- electric valves, 23- sewage pumps;

Figure 2 — Schematic diagram of ceramic membrane cleaning process;

In the figure 2, 3- ceramic membrane module filter, 4, 5- flow meter, 6- circulation pump, 7, 8, 9, 10, 11- pressure sensor, 13, 14, 15, 16, 18, 19, 20 , 21, 22, 27, 28, 29, 30, 31, 32, 33-electric valve, 24-cleaning water tank, 25-lye tank, 26-acid tank.

Figure 3 — Layout plan of the device;

In the figure 1- oily sewage tank, 2, 3- ceramic membrane module filter, 4, 5- flow meter, 6- circulating pump, 7, 8, 9, 10, 11- pressure sensor, 12, 13, 14, 15 , 16, 17, 18, 19, 20, 21, 22, 27, 28, 29, 30, 31, 32, 33, 34-electric valve, 24-cleaning water tank, 25-lye tank, 26-acid Can.

Detailed ways

In order to further disclose the technical solution of the present utility model, the following will be described in detail through the embodiments in conjunction with the accompanying drawings:

As shown in Figure 3, a method for finely treating produced water in thin interbed low permeability oilfields with ceramic membranes is characterized in that the oily sewage produced in thin interbedded low permeability oilfields is sent to the oily sewage tank, and then the oily sewage is pumped through the circulating pump Lift into the ceramic membrane module filter, use the ceramic membrane module filter in parallel or in series according to the requirements of the influent water quality and effluent water quality to treat the oily sewage produced from thin interlayer low permeability oil fields; the ceramic membrane module filter adopts the method of cross-flow filtration , driven by pressure, the oily sewage flows at a high speed on the surface of the membrane layer inside the membrane tube. The oily sewage passes through the ceramic membrane layer along the vertical direction to generate purified water and enters the sewage reinjection system. Macromolecular substances or solid particles are intercepted by the membrane. After being washed by the high-speed flowing oily sewage, it returns to the oily sewage tank, mixes with the newly added oily sewage, and then enters the ceramic membrane module filter to start the next filtration process, further increasing the yield of purified water, and continuously conveying to the sewage reinjection system Comply with reinjection water containing A1 grade water quality.

Referring to Fig. 1, before the treatment of oily sewage, close the vent electric valve 12 of the raw water tank 1 and the vent electric valve 22 of the ceramic membrane module filter, detect the oily sewage water quality in the oily sewage tank 1, to determine the ceramic membrane module filter 2, 3. Membrane pore size and operation mode. If the influent water quality is good, in order to increase the processing capacity of the device, the ceramic membrane module filters 2 and 3 can be operated in parallel, and at this time open the electric valves 13, 14, 15, 16, 18, 19, 20, 21, 34 , close the electric valve 17, and the oily sewage passes through the ceramic membrane module filters 2 and 3 at high speed under the action of the circulating pump, and the liquid of small molecular substances passes through the ceramic membrane layer and becomes purified water, which enters into this water through the electric valves 16, 19, 21 The sewage reinjection system connected to the device, macromolecular substances or solid particles are intercepted by the membrane, and under the scouring of high-speed oily sewage, the electric valve 18 and the electric valve 20 at the bottom outlet of the ceramic membrane module filter return to the oily sewage tank to make the fluid To achieve the purpose of separation, concentration and purification; if the quality of the influent water is poor, in order to ensure the quality of the effluent water of the device, the ceramic membrane module filters 2 and 3 can be operated in series, and the ceramic membrane module filter 2 can be used with a larger pore size membrane, while the ceramic membrane module filter 3 can use a membrane with a relatively small pore size. At this time, open the electric valves 13, 14, 16, 17, 19, 20, 21, 34, close the electric valves 15, 18, and the oily sewage is circulating Under the action of the pump, it passes through the ceramic membrane module filter 2 and the ceramic membrane module filter 3 successively at high speed, and the liquid of small molecular substances is filtered through the ceramic membrane layer to become purified water and enters the sewage connected to the device through the electric valves 16, 19, 21 In the reinjection process, macromolecular substances or solid particles are intercepted by the membrane, and are returned to the oily sewage tank through the electric valve 18 and the electric valve 20 under the flushing of the high-speed flowing oily sewage. The flowmeter 4 and the flowmeter 5 respectively measure the water inflow of the ceramic membrane module filter and the return flow of filtered sewage, so as to calculate the water production rate of the device through the PLC control cabinet.

When the flux of the ceramic membrane drops to a certain level, the sewage in the oily sewage tank 1 needs to be emptied in order to increase the membrane flux again. At this time, the electric valve 13 should be closed, and the electric valve 12 should be opened. The bottom row of the function is placed in the sewage receiving sewage pool connected to this device; after the oily sewage tank 1 is emptied, close the electric valve 12, and then add new oily sewage to the oily sewage tank 1 for treatment to carry out the next stage of treatment .

See Figure 2. When the membrane flux decreases to a certain extent, even if the blowdown cannot restore the membrane flux, chemical cleaning must be carried out to restore it. Chemical cleaning is generally divided into three parts: rinsing, alkali cleaning and acid cleaning. Before chemical cleaning, it is necessary to open the electric valves 18 and 22 to empty the residual oily sewage in the ceramic membrane module filter 2 and the ceramic membrane module filter 3, and then close the electric valves of the ceramic membrane module filter 2 and the ceramic membrane module filter 3. Valves 16, 19, 21 start the ceramic membrane module filter cleaning process. The chemical cleaning steps of the ceramic membrane module filter are as follows:

①Water washing: close the venting electric valve 33, add clean water in the cleaning water tank 24, close the electric valves 22, 28, 29, 30, 31, open the electric valves 13, 14, 18, 20, 27, 32, and clean water in the circulation pump Under the action of 6, the ceramic membrane module filter is circulated and cleaned to further remove the oily sewage residue in the ceramic membrane module filter;

② Alkali cleaning: add NaOH solution in the lye tank 25, close the electric valves 22, 27, 29, 30, 32, open the electric valves 13, 14, 18, 20, 28, 31, the effect of the alkali solution on the circulating pump 6 In the ceramic membrane module filter, the circulating alkaline solution is cleaned;

③Water washing: empty the residual lye in ceramic membrane module filter 2 and ceramic membrane module filter 3 after alkali washing, then repeat step ①, rinse until the cleaning water is neutral, and empty;

④ pickling: add _HNO3 solution in the acid tank 26, close the electric valves 22, 27, 28, 31, 32, open the electric valves 13, 14, 18, 20, 29, 30, and the acid solution is in the circulation pump 6 Under the action, the circulating acid solution is cleaned in the filter of the ceramic membrane module;

⑤Water washing: empty the residual acid in ceramic membrane module filter 2 and ceramic membrane module filter 3 after pickling, then repeat step ①, rinse until the cleaning water is neutral, and empty;

6. Empty: open electric valves 33, 27, 28, 29, and drain the waste liquid in the cleaning water tank 24, the lye tank 25, and the acid tank 26 in sequence to the waste liquid collection tank connected to the device. When performing step ⑤, test and record the flux of the clear water membrane. If the flux of the original membrane is reached, stop cleaning; if the flux of the original membrane is not reached, repeat the above operation until the flux is restored.

Example

The utility model has been applied on-site at Xinyi Sewage Station and Fanjia Settlement Station of Shengli Oilfield. The treatment capacity of the device is 200m ³ /d, and the ceramic membrane membrane module filter with a pore size of 50nm is adopted to operate in two stages in series to feed oily The oil content of sewage is 200mg/L～300mg/L, the concentration of suspended solids is 30 mg/L～50mg/L, and the effluent after treatment by the device has reached A1 grade water quality (average oil content=0.3mg/L, average suspended solid content=0.58 mg/L, the median value of the average suspended solid particle size = 0.928μm, and the average corrosion rate < 0.076mm/a).

During the operation of the device, the sewage needs to be discharged and filtered every 20 hours on average, and the discharge of the filtered sewage is about

2‰ of the total amount of oily sewage treatment; chemical cleaning is required every 28 to 30 days of operation. After chemical cleaning, the membrane flux can be restored to 100%, and the total water consumption is less than 3‰ of the total amount of oily sewage treatment. The generated acid, Alkali waste liquid is about 1‰ of the total amount of oily sewage treatment, which can be re-treated in this device after neutralization.

Claims (2)

1. A ceramic membrane device for finely treating thin interlayer low-permeability oilfield produced water, mainly composed of skids, raw water tanks, cleaning water tanks, lye tanks, acid tanks, ceramic membrane components, flow meters, circulation pumps, sewage Composed of pumps, mixers, electric valves and skids, it is characterized in that there is an oily sewage tank and a ceramic membrane module filter with parallel and series processes on the rear top surface of the skid, and a word on the front top surface of the skid. Arranged cleaning water tanks, lye tanks and acid tanks; the inlet of the oily sewage tank is connected to the oily sewage water pipeline, and the outlet is respectively connected to the inlet with pressure sensor of the ceramic membrane module filter through a circulation pump and a flow meter, and the ceramic membrane module The filtered purified water outlet of the filter is connected in parallel with the sewage reinjection system through a pressure sensor and an electric valve. The sewage outlet filtered by the ceramic membrane module filter is connected in parallel with the return inlet of the oily sewage tank. The pump is connected, and the outlet of the sewage pump is connected to the dirty oil pool outside the skid; the outlets of the cleaning water tank, lye tank and acid tank are connected in parallel and then connected to the inlet of the circulation pump. The return inlet of the above three tanks is connected to the ceramic membrane module through electric valves and flow meters The sewage outlet filtered by the filter is connected in parallel with the outlet pipe; the control line of the circulating pump and the sewage pump, the pressure sensor of the oily sewage inlet of the ceramic membrane filter, the pressure sensor signal line of the filtered water outlet, and all electric valves The control line is connected with the PLC control cabinet. 2. According to claim 1, the device for finely treating the produced water in thin interbedded low-permeability oilfields with ceramic membranes is characterized in that: the ceramic membrane module filter housing is configured as a cylinder, and the oily sewage inlet is arranged at the top middle, and after filtering The water outlet is set at the middle and lower part of the cylinder, and the sewage outlet is set at the bottom middle; the oily sewage inlet of the oily sewage tank is set at the top of the tank, the oily sewage outlet and sewage outlet are set at the bottom of the tank, and the return port is set at the top of the tank; the cleaning water The outlets of tanks, lye tanks and pickling tanks are located at the bottom of the tanks, and the return inlets are located at the top of the tanks.

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